1. Field of the Invention
The present invention relates generally to the design of integrated circuit, and more specifically to the implementation of a quantizer circuit which translates a sample of an input signal (amplitude/strength/sample) to a nearest values in a set of predefined reference values.
2. Related Art
A quantizer generates one of a possible set of output values with each of the set of output values representing a corresponding quantized level of a signal strength and the generated value representing the value corresponding to the quantized level closest to the strength of an input signal/sample, as is well known in the relevant arts. The translated value is generally represented using digital bits and provided as a corresponding output.
Generally, quantization is performed using a number of comparators with each comparator comparing the input signal with one of a predefined reference levels. The result of each comparison thus indicates whether the input signal exceeds the strength of the corresponding reference (quantized) level. The comparison results can then be used to generate a quantized (output) value. Thus, the number of comparators used in a quantizer in one embodiment equals the number of reference levels with which comparison is sought to be performed.
A comparator is often implemented using a pre-amplifier and a latch. The latch generates first logic value when a input signal strength is greater than the reference value and generates a second logic value otherwise. Pre-amplifiers are implemented (with a gain) to reduce various errors such as latch offset, glitches due to switching etc., at the input of the comparator as is well known in the relevant arts. However, pre-amplifiers often consume large area and power.
Thus, as the number of comparators (or quantization levels) increases, it is often desirable to reduce the number of pre-amplifier to meet various requirements such as reduced area/power consumption.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit (s) in the corresponding reference number.